attached to a FreeBSD system; we do not support SoundBlaster CDROM
interface, or other "mini SCSI" adapters.
attached to a FreeBSD system; we do not support SoundBlaster CDROM
interface, or other "mini SCSI" adapters.
-The limitation some controllers have with >16MB of memory (as noted)
-is due to the fact that the ISA bus only has a DMA address space of 24 bits.
+Some controllers have limitations with the way they deal with >16MB of memory,
+due to the fact that the ISA bus only has a DMA address space of 24 bits.
If you do your arithmetic, you'll see that this makes it impossible to do
direct DMA to any address >16MB. This limitation is even true of some
EISA controllers (which are normally 32 bit) when they're configured to
emulate an ISA card, which they then do in *all* respects. This problem
is avoided entirely by IDE controllers (which do not use DMA), true EISA
If you do your arithmetic, you'll see that this makes it impossible to do
direct DMA to any address >16MB. This limitation is even true of some
EISA controllers (which are normally 32 bit) when they're configured to
emulate an ISA card, which they then do in *all* respects. This problem
is avoided entirely by IDE controllers (which do not use DMA), true EISA
-controllers (like the UltraStor or Adaptec 1742A) or VLB (local bus)
-controllers.
-
+controllers (like the UltraStor or Adaptec 1742A) and most VLB (local bus)
+controllers. In these cases, the system will use "bounce buffers" to
+to talk to the controller, and is generally the default.
-WD8003EBT, WD8003S, WD8003SBT and WD8013EBT based clones.
+WD8003EBT, WD8003W, WD8013W, WD8003S, WD8003SBT and WD8013EBT
+based clones.